<html>
    <head>
    </head>
    <body>
        <iframe id="1" width="100%" height="300" srcdoc="<p>Hello world!</p>"></iframe>
        <iframe id="2" width="100%" height="300" srcdoc="<p>Hello world!</p>"></iframe>
        <iframe id="3" width="100%" height="100%" src="https://www.itagnesmeyer.de"></iframe>
        
    </body>
</html>